# CVE-2026-34813: Endian Firewall stored XSS in proxyuser.cgi

Source: https://junglewise.ai/threats/cve-2026-34813-endian-firewall-stored-xss-in-proxyuser-cgi  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-02. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-34813 · Severity: medium · CVSS 6.4 · Published 2026-04-02

Endian Firewall, a security appliance used to protect corporate networks, is vulnerable to a security flaw in its user management interface. An authorized user can inject malicious scripts into the system that will automatically run when other administrators view specific management pages. This could allow an attacker to hijack administrative sessions or perform unauthorized actions within the firewall management console.

Technologies: [Endian Firewall Community](https://junglewise.ai/threats/technologies/firewall-community). Vendors: [Endian](https://junglewise.ai/threats/vendors/endian).

## Quick answers

**Is CVE-2026-34813 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34813 being exploited in the wild.

**How severe is CVE-2026-34813?** Medium severity, with a CVSS score of 6.4, published 2 April 2026.

**Which products and versions are affected?** Endian Firewall 3.3.25 and prior.

**Is there a fix for CVE-2026-34813?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-34813 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-34813?** Check whether you run Endian Firewall Community. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A stored cross-site scripting (XSS) vulnerability exists in Endian Firewall versions up to and including 3.3.25. The vulnerability is located in the /cgi-bin/proxyuser.cgi component and is triggered via the 'user' parameter. An authenticated attacker with low privileges can submit a specially crafted string containing malicious JavaScript. This script is then stored on the server and executed in the context of any user (including administrators) who subsequently visits the affected page. This can lead to session hijacking, unauthorized configuration changes, or further escalation of privileges within the firewall's web interface.

## Affected products

- Endian Firewall 3.3.25 and prior

## Timeline

- 2026-04-02: disclosed
- 2026-04-02: advisory

## References

- [https://help.endian.com/hc/en-us/sections/360004371358-Community](https://help.endian.com/hc/en-us/sections/360004371358-Community)
- [https://www.vulncheck.com/advisories/endian-firewall-cgi-bin-proxyuser-cgi-user-stored-cross-site-scripting](https://www.vulncheck.com/advisories/endian-firewall-cgi-bin-proxyuser-cgi-user-stored-cross-site-scripting)

## Related threats

- [Endian Firewall stored XSS in remark parameter](https://junglewise.ai/threats/cve-2026-34823-endian-firewall-stored-xss-in-remark-parameter)
- [Endian Firewall stored XSS in certificate management interface](https://junglewise.ai/threats/cve-2026-34822-endian-firewall-stored-xss-in-certificate-management-interface)
- [Endian Firewall stored XSS in VPN user remark parameter](https://junglewise.ai/threats/cve-2026-34821-endian-firewall-stored-xss-in-vpn-user-remark-parameter)
- [Endian Firewall stored XSS in IPsec remark parameter](https://junglewise.ai/threats/cve-2026-34820-endian-firewall-stored-xss-in-ipsec-remark-parameter)
- [Endian Firewall stored XSS in openvpnclient.cgi](https://junglewise.ai/threats/cve-2026-34819-endian-firewall-stored-xss-in-openvpnclient-cgi)